This population-based, case-control epidemiologic study will examine whethe reproductive factors and exogenous homone use affect women's risk of Hodgkin's disease (HD), a poorly understood lymphoma. HD rates are lower in adult women than men, particularly at reproductive ages. Although the descriptive epidemiology of HD suggests a protective effect of childbearing and both clinical and experimental data show an inhibitory effect of pregnancy on lymphomas, no reproductive or homone-use factors except parity have ever been evaluated regarding HD risk. The two prior studies considering parity and HO risk found strong but opposing associations. This discrepancy requires resolution, and the unexplored hypothesis of hormonal influence on HD risk suggested by existing evidence needs evaluation. Specific study aims are: 1) to detemine if parity protects against HD risk, and if the effect is long-term or temporary (suggesting tumor suppression during pregnancy);2) to determine whether other reproductive factors independently affect HD risk; 3) toexplore the effects of exogenous hormone use on HD risk; 4) to examine the above risks among histologic-type subgroups; 5) to control throughout for potential confounders (e.g., social class). The proposed 5-year study will include 315 women newly diagnosed with histologically confirmed HD, and 315 control women, from 9 counties in the San Francisco Bay Area. Cases will be ascertained through population-based tumor registries. Population-based controls will be identified by random-digit dialing, and requency-matched to cases on age, race and phone number area-code and Prefix. All subjects ill be interviewed in person about demographics (including social status); medical istory; menstrual and fertility history; reproductive experience (age at, duration of and utcome of each pregnancy; lactation); and exogenou hormone use. Relative risks assocated with study factors will be estimated with logistic regression methods for HD overall nd by histologic subtype, with adjustment for social class and other confounders. Study trengths include: 1) a new and feasible approach to investigating the etiology of a cancer hat, by affecting young as well as older persons, is of particular public health concern; thorough examination of the hormone-influence hypothesis through investigation of a full factors; 3) use of population-based cases, for complete, unbiased ugh subjects to detect 2- to 3-fold associated risks for HD overall type; 4) use of population-based controls, reducing biases from s; and 5) detailed attention to suspected confounding factors,